1. Field of the Invention
The present invention relates to an endoscope system having a drum, about which an insertion member of an endoscope is wound, stowed in a case.
2. Related Art Statement
An endoscope system having an insertion member elongated to be so long as to enable endoscopic inspection of a deep part of a plant is sometimes used as an endoscope system for industrial. In this case, if the elongated insertion member is left as it is, the endoscope system is no user-friendly. A drum-inclusive endoscope system is therefore sometimes employed, wherein the elongated insertion member is wound about a drum with its portion of a required length made usable.
For example, Japanese Laid-open Utility Model Publication No. 58-172905 discloses a container for endoscopes in which a scope stowage drum is encased in a carrier case. The container accommodates an endoscope alone, but does not accommodate the other system-related equipment.
Moreover, Japanese Laid-open Patent Application Publication No. 1-204014 discloses an endoscope system having a rubbertuator drive unit, a CCU, and a light source incorporated in a drum. The drum included in the endoscope system is left bared. No consideration is taken into transportability of the system.
There is therefore a demand for an endoscope system that is taken account at least of the transportability of the system. Japanese Patent Publication No. 5-56486 discloses an endoscope unit system in which a drum and a camera control unit (hereinafter CCU) are incorporated in a main unit in efforts to improve the ease of carrying or stowing an endoscope and the maneuverability of the endoscope such as the smoothness in inserting the endoscope. The CCU includes a signal processor for processing an image signal sent from a solid-state imaging device to produce a video signal. However, in the system, the endoscope does not have an angle controlling mechanism.
Moreover, Japanese Laid-open Patent Publication No. 4-81711 discloses an endoscope system, which includes an operator unit, an stowage unit, and a control unit, in efforts to realize a compact design and an ease of manipulation and to improve the maneuverability of the endoscope. The operator unit is used to set an angle of bending of a bending section. A flexible tube including the bending section is taken up and stowed in the stowage unit. The control unit is included in the stowage unit, and controls a fluid pressure to be applied to the bending section according to a set value from the operator unit. In the endoscope system, each equipment and a drum are separated from each other. The entire system including the drum is integrated into a case.
Furthermore, U.S. Pat. No. 5,323,899 discloses a video probe case in which an entire system is stowed in the form of one package. An endoscope integrated with a CCU and a light source are stowed mutually separately in the case.
German Patent No. DE19748795 discloses an endoscope system including a drum, an angle controlling mechanism, a CCU, and a light source.
However, in the endoscope unit system disclosed in the Japanese Laid-open Patent Publication No. 5-56486, the drum, light source, and CCU are integrated into the main unit. This leads to greatly improved maneuverability. However, when an insertion member is wound up, since the drum is bared, various operator buttons provided on the endoscope are exposed. Moreover, the entire system suffers from poor transportability. Moreover, there is difficulty in improving the resistance to shocks or to an environment.
Moreover, in the endoscope system disclosed in the Japanese Laid-open Patent Application Publication No. 4-81711, respective equipments are independently stowed in different cases. An unnecessarily large space is therefore occupied for stowage. The respective equipments cannot be stowed compactly. Moreover, it is time-consuming to lead numerous signal lines and a light guide fiber, which run through the insertion member of the endoscope, to the respective equipments by way of the drum. The structure of the drum is complex.
Moreover, according to the U.S. Pat. No. 5,323,899, respective equipments are independently stowed in the video probe case respectively. The use efficiently of a space is so poor that the case is very large. Besides, when an endoscope is used, a large heavy operator unit with an incorporated-in motor-driven angle controlling mechanism must be taken out from the case. The maneuverability is therefore poor. Furthermore, the endoscope is stowed alone. The video probe case is not of a drum-inclusive type.
Moreover, according to the German Patent No. DE19748795, the endoscope system is designed in consideration of a capacity for stowing an insertion member. However, the drum about which the insertion member is wound up is left bared. Various operator buttons provided on the endoscope are left exposed. No consideration is taken into a capacity for stowing a controller and other members to be stowed. This poses the same problem as the problem underlying the endoscope unit system disclosed in the Japanese Laid-open Patent Publication No. 5-56486.
Moreover, according to, for example, Japanese Unexamined Patent Application Publication No. 1-138522 and Japanese Examined Utility Model Publication No. 4-35850, a bearing means for rotatably bearing a drum freely is mounted on a shaft whose center coincides with the center of rotation of the drum.
However, when a rotational bearing structure is adopted, since a rotational bearing penetrates through the drum along the rotation center shaft of the drum, the presence of the rotational bearing affects the layout of respective equipments to be stowed in the drum. This results in an increase in the size of the drum.
Moreover, when the rotational bearing is formed on the outer circumference of the rotation center shaft of the drum, a signal line splicing structure or the like including a slip ring is needed to electrically connect equipment stowed in the drum to external equipment. The inclusion of the structure and the rotational bearing structure makes the structure of the drum complex and increases the size of the drum.
Conventionally, a method of checking an index line inscribed on an insertion member has been employed as a means for sensing by what length the insertion member is wound about an insertion member take-up drum or for sensing by what length the insertion member is extended from the drum.
In this case, there is a drawback that even when an attempt is made to control various relevant equipments according to the length by which the insertion member is wound about the drum, information of the length cannot be automatically supplied to the equipments.
In contrast, according to Japanese Laid-open Patent Publication No. 10-274743, a length of movement by which an insertion member (referred to as a coil spring in the publication) is drawn out is detected by counting the number of pulses output from rotary encoders coupled to the rotation shafts of a pair of rollers that sandwiches the insertion member.
According to the above publication, the information of the length by which the insertion member is drawn out can be outputted electrically. However, part of the detecting means is mechanically driven. The number of pulses generated from the rotary encoders is counted for electrically detecting the length of movement. Therefore, only when the power supply is turned on, the length is measured and the information of the length is outputted. Whenever the power supply is turned on, the insertion member must be initialized to the same state. Otherwise, length information cannot be acquired accurately.
Moreover, when the power supply is temporarily turned off during use, the length by which the insertion member is drawn out cannot be measured during the period during which the power supply is off. There is therefore a fear that a value measured with the power supply turned on may be inaccurate. For preventing this incident, when the power supply is turned off, the length by which the insertion member is drawn out must be held unchanged carefully. This is no user-friendly.
Moreover, in the drum-inclusive endoscope system, the insertion member is exposed to outside. This is inconvenient for transporting the endoscope system. Moreover, from the structural viewpoint, it is hard to protect the endoscope system from shocks during transportation. Japanese Laid-open Patent Publication No. 2000-89131 discloses an endoscope system structured to protect components with a housing.
For protecting the contents of the housing from shocks, it is conceivable to interpose shock absorbers between the surfaces of the housing that may undergo the shocks and the contents thereof, though the shock absorbers are not included in the endoscope system described in the Japanese Laid-open Patent Publication No. 2000-89131. However, when the shock absorbers are placed on the surfaces that may undergo shocks, the housing must be made larger by dimensions required for the inclusion of the shock absorbers. When the housing is confined to the smallest possible size and the number of shock absorbers is made smaller than a required number of shock absorbers, the contents of the housing may be broken due to shocks.